1. Field of the Invention
The present invention relates to a turbo fan and an air conditioner having the same applied thereto, and more particularly, to a turbo fan having a flow characteristic of an axial fan, and an air conditioner having the turbo fan employed as a fan for an outdoor unit.
2. Background of the Related Art
In general, the air conditioner circulates cooled, or heated air in a room for comfort. The air conditioner requires many fans for producing air flow passing through heat exchangers. The fans may be axial, or centrifugal.
The axial fan draws and discharge air in a direction parallel to an axial direction, and the centrifugal fan draws air in a direction parallel to the axial direction, but discharges the air in a centrifugal direction. In the centrifugal fans, there are a sirocco fan, and a turbo fan. A related art turbo fan will be explained, briefly.
Referring to FIG. 1, the related art turbo fan is provided with a hub 1 having a boss 2 in a central part for coupling with a driving shaft of a motor, a plurality of blades 3 each fitted in a radial direction along a periphery of the hub 1 prolonged in an axial direction, and a shroud 4 fitted to one ends of the blades 3. The shroud 4 has an inlet part 4a parallel to an axial direction to form an inlet, and a curved part 4b bent outward from the inlet part 4a having one ends of the blades 3 connected thereto.
The operation of the turbo fan will be explained, briefly. When the hub 1 is rotated by a rotating force of the motor, an air flow is produced by forms of the blades 3. That is, after being drawn through the inlet of the shroud 4, the air is discharged through spaces between blades 3, i.e., in a centrifugal direction, which is best shown in FIG. 1 by arrows.
The turbo fan, having the foregoing flow characteristic, has a high efficiency and a low noise compared to other kind of fans, particularly, to the axial fan.
However, the turbo fan is employed only in an indoor unit of the air conditioner due to the flow characteristic. It is because, as there are many refrigerating cycle elements, such as an outdoor heat exchanger, and a compressor, fitted in the outdoor unit of the air conditioner, the axial fan, producing an axial air flow, is more favorable than the turbo fan for reducing a total size of the outdoor unit. Owing to this reason, the turbo fan having a high efficiency and less noise can not be employed in the outdoor unit.
Particularly, in a unit type air conditioner, having the indoor unit and the outdoor unit fitted in one unit, the foregoing problem becomes very serious. That is, the unit type air conditioner, not only transmits the noise form the axial fan to the room, but also has a substantially great power consumption caused by the low efficiency of the axial fan.
In the meantime, unitary formation of the related art turbo fan is not easy. It is because molding of related art turbo fan is not possible owing to a structure of the related art turbo fan. Consequently, the related art turbo fan is fabricated by separate formation, and welding of the hub 1, the blades 3, and the shroud 4, which has a complicated fabrication process, and costs high, at the end.